Electric toothbrush

ABSTRACT

The invention is directed to an electric toothbrush having a brush section and a drive shaft received in the brush section. The brush section includes a first bristle supporting structure operatively coupled to the shaft for motion about an axis essentially perpendicular to a longitudinal axis of the shaft, and a second bristle supporting structure operatively coupled to the shaft for substantially transverse oscillating motion of the entire second bristle supporting structure relative to the longitudinal axis of the shaft. The first bristle supporting structure is generally cylindrically shaped and carries a plurality of bristle clusters.

This is a continuation of application Ser. No. 08/507,372, filed asPCT/EP94/00704 published as WO Mar. 8, 1994 now U.S. Pat. No. 5,732,433.

BACKGROUND

This invention relates to an electric toothbrush, with a brush sectionin which a rotatably carried shaft is received and on which a bristlesupporting structure coupled to the shaft is rotatably mounted, and withmeans for driving the shaft in an alternating motion.

An electric toothbrush of this type is known from German publishedpatent application DE 39 37 850 A1 which is incorporated in thedisclosure content of the present application by express reference. Inthis application, the alternating rotary motion of the shaft istransmitted to the bristle supporting structure by means of a bevel geararrangement. The bristle supporting structure carries a plurality ofbristles whose free ends form an approximately circular cleaningsurface. With the electric toothbrush in activated condition, thiscleaning surface performs an alternating rotary motion about itsvertical axis. The operator of the toothbrush may use the cleaningsurface for cleaning both the tooth surfaces and the interproximalspaces, in addition to massaging the gums.

From German design patent M 92 03 436 a push-on brush attachment for anelectric toothbrush is known in which a bristle supporting structure isintegrally formed with the stem of the brush. The bristle supportingstructure includes a plurality of bristles whose free ends form anelongate cleaning surface, as well as a single bristle cluster whosebristles taper to a point. The cleaning surface essentially serves thepurpose of cleaning the tooth surfaces, while the bristle cluster isintended for cleaning spaces between adjacent teeth. With the electrictoothbrush activated, the movements produced by the bristles of thecleaning surface and the single bristle cluster are identical.

SUMMARY

It is an object of the present invention to provide an electrictoothbrush of the type initially referred to with which an improvedcleaning action, also of the interproximal spaces, can be accomplished.

This object is essentially solved by providing an interproximal brushwhich is coupled to the shaft independently of the coupling of thebristle supporting structure to the shaft.

Using an electric toothbrush of the type initially referred to, it ispossible by means of the interproximal brush to clean interproximalareas particularly easily and thoroughly. However, rather than arrangingthe interproximal brush on the bristle supporting structure and couplingit to the shaft via the bevel gear arrangement, the interproximal brushis coupled to the shaft independently of the bristle supportingstructure. It is thereby possible to impart a preferably alternatingrotary motion about an axis substantially normal to the shaft to thebristle supporting structure, while imparting an alternating pivotalmotion or reciprocating motion about the axis of rotation of the shaftto the interproximal brush. With the electric toothbrush in activatedcondition, the user is in a position to clean the tooth surfaces usingthe cleaning surface of the oscillating bristle supporting structure, inaddition to cleaning the interproximal spaces using the interproximalbrush that performs a pivotal or reciprocating motion. Cleaning of theteeth is thus essentially accomplished by means of the free ends of thebristles of the bristle supporting structure providing the cleaningsurface, while the bristles of the interproximal brush are intended toperform a supplementary, still more efficient cleaning function of theinterproximal spaces.

In an advantageous configuration of the electric toothbrush, theinterproximal brush is arranged at a distance to the bristle supportingstructure. This enables the interproximal brush to penetrate betweenadjacent teeth deeply, without the bristles that form the cleaningsurface being in a position to prevent this from occurring due to theirengagement against the tooth surfaces.

In a further advantageous configuration, the interproximal brush isdisposed angularly, in particular at approximately right angles, withrespect to the shaft. It is thereby accomplished that the interproximalbrush performs a kind of wiping motion over a maximum possible surface,thus producing a superior cleaning action in the interproximal spaces.

Conveniently, the interproximal brush is arranged in the area of thebrush section, with an opening being provided in the brush sectionthrough which the interproximal brush is passed. In this manner, accessto the shaft accommodated in the brush section is not open, thusprotecting the user of the electric toothbrush well from the possibilityof injury by these components.

In an advantageous further feature of the electric toothbrush, theinterproximal brush includes a mount in which at least one, inparticular two bristle clusters are held. The bristle clusters aresuitably arranged side-by-side in the direction of pivotal motion of theinterproximal brush. By arranging bristle clusters in this manner, easeof penetration of the bristles of the bristle clusters between theuser's teeth is accomplished.

The possibility exists to join this mount to the shaft by adhesivebonding or by welding to provide a nonrotative connection with theshaft. These methods present a simple and reliable way of fastening theinterproximal brush to the shaft.

However, it is also possible in an advantageous manner to provide themount with one or several trunnions and the shaft with one or severalassociated bores for fitting the mount therein. This type of couplingthe interproximal brush to the shaft can be strengthened by the addedprovision of adhesive bonding or welding.

In another advantageous configuration of the electric toothbrush, thebristles of the bristle supporting structure extend approximately in thesame direction as the bristles of the interproximal brush.Advantageously, the bristles of the interproximal brush are of greaterlength than the bristles of the bristle supporting structure. Thisenables the bristles of the interproximal brush to penetrate between theuser's teeth with ease.

It has proven to be suitable to arrange for the shaft to rotate throughan angular range of ±35 degrees, approximately. The pivotal range of theinterproximal brush is thus of the same magnitude which ensures a goodcleaning action.

In a still further configuration of the present invention, the mount hasa bore in a base section thereof and is located in position on the shaftby means of a pin. This configuration has proven to be suitableparticularly in an embodiment of the toothbrush as described in Germanpatent application P 42 39 251. For one thing, this type of locationenables the toothbrush to be assembled with ease, and for another thing,this type of location is highly economical.

By reason of the fact that the pin has one end received in a bore of theshaft and its other end in a bore of the mounting tube, with the boresbeing disposed concentrically with an axis of rotation of the shaft, thepin ensures an additional bearing function of the shaft in relation tothe axis of rotation, aside from providing a locating function for themount.

In a suitable further feature of the present invention, a rib structurearranged at the base section of the mount is received in a grooveprovided on the shaft. By this means, in particular in combination withthe pin extending through the mount, the mount is located in position onthe shaft in an extremely secure and lasting fashion.

In another advantageous configuration of the present invention, thebristle supporting structure has on its periphery a recess in the formof a circular segment. This affords the possibility of arranging themount in very close proximity to, or even in the area of, the bristlesupporting structure, thus providing in particular a highly compact andhandy cleaning head of the brush.

Advantageously, the mount is disposed in the immediate vicinity of thebristle supporting structure and/or integrally formed therewith.

In a further feature of the present invention, the bristles of the mounthave a larger diameter and/or a higher stiffness than the bristles ofthe bristle supporting structure. This increases the stability of thelonger bristles of the interproximal brush to a sufficient degree, sothat their penetration between the user's teeth is ensured.

Still further, the combined cleansing motions of the interproximal brushwith the round brush have afforded the possibility of fixing the angleof rotation of the bristle supporting structure at values in the rangeof ±25 degrees, approximately. Owing to the cleansing action of theadditional interproximal brush, the angle of oscillation of the bristlesupporting structure can be reduced, thus enabling the expenditure forthe gearing of the bristle supporting structure to be lowered. Anotheradvantage resulting from reducing the angle of rotation of the bristlesupporting structure is that the gearing is exposed to less severe loadsthan in cases where the oscillation angles are greater.

Further features, advantages and application possibilities of thepresent invention will become apparent from the subsequent descriptionof embodiments illustrated in more detail in the accompanying drawings.It will be understood that any single feature and any combination ofsingle features described and/or represented by illustration form thesubject-matter of the present invention, irrespective of theirsummarization in the claims and their back-references.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a, 1b are, respectively, a top plan view and a side view, partlyin section, of a brush section of an electric toothbrush illustrating anembodiment of the present invention in simplified form;

FIG. 2 is a longitudinal sectional view of the brush section of FIGS. 1aand 1b;

FIG. 3 is a cross-sectional view of the brush section of FIGS. 1a and 1bin the area of the interproximal brush, illustrating a first type offastening;

FIG. 4 is a cross-sectional view of the brush section of FIGS. 1a and 1bin the area of the interproximal brush, illustrating a second type offastening;

FIG. 5 is a partial longitudinal sectional view of the brush section inthe area of the interproximal brush, illustrating a further type offastening;

FIG. 6 is a sectional view of the mount of the interproximal brush,taken along the line B--B of FIG. 5; and

FIG. 7 is a top plan view of a further embodiment illustrated insimplified form.

DESCRIPTION

The subsequent description relates to a further development of thetoothbrush disclosed in German published patent application DE 39 3 850A1 as well as of German patent application P 42 39 251.9 with analternative gearing for the bristle supporting structure, whosedisclosure content is incorporated in the present application by expressreference.

FIGS. 1a and 1b of the present application illustrate schematically in atop plan view and, respectively, a side view a brush section 24 of anelectric toothbrush of the invention. The brush section 24 is comprisedof a hollow mounting tube 36 receiving rotatably therein a shaft 75. Abristle supporting structure 38 carrying bristles 45 combined intoindividual tufts is rotatably mounted at the free end of the brushsection 24.

In a manner not shown, the shaft 75 is coupled to means 150 imparting analternating rotary motion to the shaft 75 about the shaft longitudinalaxis. The angular range through which the shaft 75 may be rotated is ±35degrees, approximately.

Referring to FIG. 2, the axis of rotation of the shaft 75 and the axisof rotation of the bristle supporting structure 38 are preferablyarranged at approximately right angles to each other. The bristlesupporting structure 38 is provided with a bevel gear 47 meshing with abevel gear segment 48 disposed at the head end of the shaft 75. Thisbevel gear arrangement provides for transmission of the alternatingrotary motion of the shaft 75 to the bristle supporting structure 38. InFIG. 1a, the direction of rotation of the shaft 75 is identified by thereference numeral 90, while the direction of rotation of the bristlesupporting structure 38 is designated by the reference numeral 91.

According to FIGS. 1a, 1b and 2, an interproximal brush 100 is arrangedat a distance to the bristle supporting structure 38 and approximatelyin the area of the brush section 24. The interproximal brush 100protrudes from the shaft 75 at about a right angle thereto, beingfixedly connected with the shaft and extending outwardly through anopening 108 in the mounting tube 36. Neglecting the pivotal motion, thebristles 109 of the interproximal brush 100 extend in about the samedirection as the bristles 45 of the bristle supporting structure 38.Further, the bristles 109 of the interproximal brush 100 are inparticular about 1 to 2 mm longer than the bristles 45 of the bristlesupporting structure 38.

The interproximal brush 100 includes a mount 101 in which the bristles109 are held. The bristles 109 are combined to form in particular twobristle clusters 102, 103 disposed transversely to the shaft 75 inside-by-side arrangement.

In a first type of fastening, the mount 101 is joined to the shaft 75 bymeans of adhesive bonding or welding. In a second type of fastening, themount 101 has on its underside two trunnions 104, 105 fitted into matingbores 106, 107 in the shaft 75. This second type of fastening the mount101 to the shaft 75 may be further strengthened by the added provisionof adhesive bonding or welding.

Being rotationally fixed relative to the shaft 75, the interproximalbrush 100 performs an alternating pivotal motion about the axis ofrotation of the shaft 75 when the electric toothbrush is activated,which motion is designated by the reference numeral 92. As the shaft 75rotates in alternating directions, the interproximal brush 100 executesa wiper-type pivotal motion serving in particular interproximal cleaningneeds. The alternating rotary motion of the bristles 45 of the bristlesupporting structure 38 being used for cleaning substantially theoutside surfaces of the teeth.

In a further embodiment, the mount 101 is positioned in relation to theshaft 75 by means of a pin 120 (FIGS. 5, 6). To this end, the mount 101has in a base section 134 thereof a bore 124. Further, a rib structure126 may be disposed at the lower end of the base section 134. At itshead end, the shaft 75 is provided with a bore 128, in particular ablind-end bore. A forward head section 136 of the mounting tube 36includes equally a bore 130 which may also be configured as a blind-endbore. The center lines of the bores 128 and 130 are coincident with theaxis of rotation 122 of the shaft 75. The head end of the shaft 75 mayhave an extension on one side in the form of a web member 138 includinga groove, not shown in the drawings, in the axial direction forreceiving, where applicable, the rib structure 126 formed on the basesection 134. To mount the interproximal brush 100 on the brush section24, the pin 120 is fitted into the bore 128, and the shaft 75 which isinitially outside the mounting tube 36 is introduced into the open endof the mounting tube 36. The interproximal brush 100 is fitted into theopening 108 from above, and the shaft 75, together with the pin 120, ispushed in the mounting tube 36 in the direction of the head section 136.As this occurs, the pin 120 passes through the bore 124 in the basesection 134 of the mount 101 and is received within the bore 130 in thehead section 136 of the mounting tube 36. By this means, not only is themount 101 fixedly secured in place on the shaft 75, but also a bearingof the head end of the shaft 75 is accomplished in relation to the axisof rotation 122.

According to a still further embodiment, the bristle supportingstructure 38 may include a recess in the form of a circular segment 132covering an angular range that corresponds approximately to the angle ofoscillation of the bristle supporting structure 38. In the area of thiscircular segment 132, the mount 101 of the interproximal brush 100 isthen arranged in the immediate vicinity of the bristle supportingstructure. Due to such integration of the mount 101 in the area of thebristle supporting structure 38, a compact cleaning head having a singlebristle cluster is obtained, in which a plurality of bristles 45 performan oscillatory motion about the center line of the bristle supportingstructure 38, while the bristles 109 of the interproximal brush 100perform an oscillatory motion about the axis of rotation 122 of theshaft 75. Also in this embodiment, the bristles 109 of the interproximalbrush 100 are of a longer configuration than the bristles 45. To enhancestability of the longer bristles 109, these are advantageously of athicker configuration than the bristles 45 or are of greater stiffnessas a result of the material selected.

We claim:
 1. An electric toothbrush comprising:a brush section and adrive shaft received in said brush section, said brush sectionincludinga first bristle supporting structure operatively coupled to theshaft for motion about an axis essentially perpendicular to alongitudinal axis of the shaft, said first bristle supporting structurebeing generally cylindrically shaped and carrying a plurality of bristleclusters, and a second bristle supporting structure operatively coupledto the shaft for substantially transverse oscillating motion of theentire second bristle supporting structure relative to the longitudinalaxis of the shaft.
 2. The electric toothbrush as claimed in claim 1wherein the second bristle supporting structure is arranged at adistance to the first bristle supporting structure such that the secondbristle supporting structure cleans interproximally while the firstbristle supporting structure cleans outside teeth surfaces.
 3. Theelectric toothbrush as claimed in claim 1 wherein the second bristlesupporting structure is arranged at approximately right angles withrespect to the shaft.
 4. The electric toothbrush as claimed in claim 1wherein the second bristle supporting structure includes a mount inwhich at least one bristle cluster is held.
 5. The electric toothbrushas claimed in claim 4 wherein the mount is disposed in the immediatevicinity of the first bristle supporting structure.
 6. The electrictoothbrush as claimed in claim 1 wherein the second bristle supportingstructure holds bristles extending approximately in the same directionas the bristle clusters of the first bristle supporting structure. 7.The electric toothbrush as claimed in claim 1 further comprising thesecond bristle supporting structure holding bristles of greater lengththan the bristle clusters of the first bristle supporting structure. 8.The electric toothbrush as claimed in claim 1 further comprising meansfor driving the shaft in an alternating motion.
 9. The electrictoothbrush as claimed in claim 1 further comprising the second bristlesupporting structure carrying a plurality of bristle clusters.
 10. Theelectric toothbrush as claimed in claim 1 wherein the plurality ofbristle clusters are arranged in only a single row.
 11. The electrictoothbrush as claimed in claim 1 wherein the second bristle supportingstructure is directly coupled to the shaft.
 12. The electric toothbrushas claimed in claim 1 wherein the shaft rotates about the longitudinalaxis.
 13. An electric toothbrush comprising:a brush section and arotatably carried shaft received in said brush section, said brushsection including a bristle supporting structure coupled to the shaftfor motion about an axis perpendicular to an axis of rotation of theshaft, and only a single row of interproximal brushes coupled to theshaft.
 14. The electric toothbrush as claimed in claim 13 wherein saidinterproximal brushes are spaced from said bristle supporting structuresuch that said interproximal brushes clean interproximally while saidbristle supporting structure cleans outside teeth surfaces.